This invention relates to the construction of basic oxygen converters used for the production of steel. It relates particularly to a fluid coupling used in the trunnion pins of a basic oxygen furnace. The coupling is used to connect a number of fluid supply conduits to a member of fluid distribution conduits used in the operation of the basic oxygen furnace.
In recent years, there has been a trend to injecting a number of reactive and non-reactive gases through the bottom of the basic oxygen furnace, which gases are most conveniently supplied through a hollow trunnion pin and then to gas distribution conduits connected to tuyeres in the bottom of the furnace. In addition, some components of the basic oxygen furnace are water-cooled to prolong the service life of these components. The cooling water is also frequently supplied through a hollow trunnion pin. Supplying both the gases and the cooling water through the hollow trunnion pin permits the furnace to rotate from a vertical operating position to an inclined charging or discharging position without the interference of a number of external gas and cooling water supply lines.
Since the trunnion pins support the tremendous weight of the furnace and the molten steel in the furnace, it is important that the several fluid supply systems be installed in such a manner that their maintenance and repair will not require the disassembly of the supporting trunnion pins.
In the past there have been a number of ideas patented relating to the handling of fluids in a hollow trunnion pin of a basic oxygen furnace. The most significant of these patents are:
U.S. Pat. No. 3,795,389--Kennedy; 1974, PA1 U.S. Pat. No. 4,098,497--Weihbold; 1978, PA1 U.S. Pat. No. 4,138,097--Farber; 1979, PA1 U.S. Pat. No. 4,284,266--Nagati; 1981, PA1 U.S. Pat. No. 4,325,540--Seki Et Al; 1982, PA1 U.S. Pat. No. 4,387,884--Seki Et Al; 1983.
These patents generally describe various types of fluid conduit joints or couplings that are free to rotate when the furnace rotates on its trunnions. However, the fluid conduit joints or couplings shown in these prior patents are complex and do not permit easy routine maintenance of the fluid supply and distribution conduits. The designs described in these prior patents often require a complete disassembly of the entire trunnion pin to replace or repair a gas distribution conduit. Such a complete disassembly requires the furnace be taken out of service for an extended period of time.
A further disadvantage of the rotary joints or couplings described in these prior patents is that they tended to leak cooling water during service. These joints and couplings usually used O-rings as seals between the several components to permit rotary movement. The O-rings frequently failed prematurely, causing a leak. The explosive potential of water and molten steel is well known and therefore such rotary joints and couplings were not favored by the steelmakers.